"Belt devices?"

I saw on SFP(don't worry, there's no way that I'll buy from them, I was just looking) that there were belt devices for boba. Were they there in either ESB or ROTJ, and where would they go, on the ammo belt? Thanks

The only place you find them is on the Don post Statue of Boba Fett, there inside the belt.

Thank you, I was quite puzzled.